diff --git a/include/linux/memfd.h b/include/linux/memfd.h index c159e40e3f34..272479317cf1 100644 --- a/include/linux/memfd.h +++ b/include/linux/memfd.h @@ -2,10 +2,19 @@ #ifndef __LINUX_MEMFD_H #define __LINUX_MEMFD_H +#include #include #define MEMFD_ANON_NAME "[memfd]" +static inline int memfd_check_seals_mode(unsigned int seals, umode_t old_mode, + umode_t new_mode) +{ + if ((seals & F_SEAL_EXEC) && ((old_mode ^ new_mode) & 0111)) + return -EPERM; + return 0; +} + #ifdef CONFIG_MEMFD_CREATE extern long memfd_fcntl(struct file *file, unsigned int cmd, unsigned int arg); struct folio *memfd_alloc_folio(struct file *memfd, pgoff_t idx); diff --git a/mm/shmem.c b/mm/shmem.c index af21a89abb0f..6df0237832c0 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -77,6 +77,7 @@ static struct vfsmount *shm_mnt __ro_after_init; #include #include #include +#include #include #include #include @@ -1546,10 +1547,11 @@ static int shmem_setattr(const struct mnt_idmap *idmap, if (error) return error; - if ((info->seals & F_SEAL_EXEC) && (attr->ia_valid & ATTR_MODE)) { - if ((inode->i_mode ^ attr->ia_mode) & 0111) { - return -EPERM; - } + if (attr->ia_valid & ATTR_MODE) { + error = memfd_check_seals_mode(info->seals, inode->i_mode, + attr->ia_mode); + if (error) + return error; } if (S_ISREG(inode->i_mode) && (attr->ia_valid & ATTR_SIZE)) { @@ -5404,12 +5406,35 @@ static const struct file_operations shmem_file_operations = { #endif }; +#ifdef CONFIG_TMPFS_POSIX_ACL +static int shmem_set_acl(const struct mnt_idmap *idmap, struct dentry *dentry, + struct posix_acl *acl, int type) +{ + struct inode *inode = d_inode(dentry); + umode_t mode = inode->i_mode; + int error; + + if (type == ACL_TYPE_ACCESS) { + error = posix_acl_equiv_mode(acl, &mode); + if (error < 0) + return error; + error = memfd_check_seals_mode(SHMEM_I(inode)->seals, + inode->i_mode, mode); + if (error) + return error; + } + return simple_set_acl(idmap, dentry, acl, type); +} +#else +#define shmem_set_acl simple_set_acl +#endif + static const struct inode_operations shmem_inode_operations = { .getattr = shmem_getattr, .setattr = shmem_setattr, #ifdef CONFIG_TMPFS_XATTR .listxattr = shmem_listxattr, - .set_acl = simple_set_acl, + .set_acl = shmem_set_acl, .fileattr_get = shmem_fileattr_get, .fileattr_set = shmem_fileattr_set, #endif